In some pump applications, it may be desirable to pump a relatively large volume of water at a relatively low pressure. Some examples of such applications may include marine vessel propulsion and irrigation systems. It is also desirable for the pump to operate efficiently.
However, in some cases, unavoidable inefficiencies may be introduced. For example, in a jet propulsion system for hydrofoil marine vessels, the inlet must be located below the hydrofoils. If the propulsion system is located in the hull, then water must be raised from the inlet to the pump, thereby reducing inlet pressure, adding other unrecoverable losses, and introducing undesirable pitching moments resulting from the high thrust line. Increasing efficiency in such cases entails matching a ratio of pump outlet flow velocity to marine vessel velocity. However, matching velocity ratios for efficiency currently involves large gears, large pumps, and large water flows.
The foregoing examples of related art and limitations associated therewith are intended to be illustrative and not exclusive. Other limitations of the related art will become apparent to those of skill in the art upon a reading of the specification and a study of the drawings.